Butterfly valve is a kind of valve which opens, closes and regulates the fluid channel by rotating around 90 degrees with disc-type headstock. Butterfly valve Not only simple structure, small size, light weight, the material consumption of the province, installation size small, and driving torque is small, easy to operate, rapid, and can also have a good flow of cell function and closure of the sealing characteristics, is the fastest development in the past more than 10 years, one of the valve varieties. Especially in the United States, Japan, Germany, France, Italy and other industrialized countries, butterfly valve is widely used. The variety and quantity of its use continues to expand, and to high temperature, high pressure, large caliber, high tightness, long life, excellent regulation characteristics and a valve multi-function direction, its reliability and other performance indicators are up to a higher level, and has been partially replaced by globe Valves, gate valves and ball valves. With the progress of butterfly valve technology. In the foreseeable short time, especially in the medium and large size, medium and low pressure in the use of the field, the butterfly valve will become the dominant valve form.
The original butterfly valve is a simple, tightly closed baffle valve. Usually used as flow regulating valve and damping valve in the plumbing system.
With the application of chemical-resistant synthetic rubber in butterfly valves, the performance of the butterfly valve is improved. Because of the corrosion resistance of synthetic rubber, anti-erosion, dimensional stability, resilience, easy to form, low cost and other characteristics, and according to different requirements of the use of different performance of synthetic rubber to meet the operating conditions of butterfly valve, thus widely used in the manufacture of butterfly valve lining and resilient valve seat.
Because Teflon (PTFE) has strong corrosion resistance, stable performance, not easy to aging, low friction coefficient, easy to shape, stable size, and can also be filled, add appropriate materials to improve its overall performance, to obtain better strength, lower friction coefficient of the butterfly valve sealing material, to overcome the partial limitations of synthetic rubber, As a result, the high polymer polymeric materials and their filler modified materials are widely used in butterfly valves, so that the performance of the butterfly valve is further improved, and the butterfly valve with more temperature, wider pressure range, sealing performance and longer service life is found.
In order to meet the high and low temperature, strong erosion, long life and other industrial applications, the use of metal seal butterfly valve has been greatly developed in recent more than 10 years. With high temperature resistance, low temperature, strong corrosion resistance, strong erosion, the application of high strength alloy material in butterfly valve makes the metal seal butterfly valve widely used in the industrial fields, such as high-low temperature, strong erosion, long life and so on, with large diameter (9750mm), High pressure (2.2kn/cm2) and wide temperature range (- 102~606℃ butterfly valve, so that the butterfly valve technology to achieve a new level.
The design and manufacture of butterfly valve has reached a new level because of the application of CAD and Computer Aided Manufacturing (CAM) and flexible manufacturing system (FMS) in the valve industry. Not only the overall innovation of the design and calculation of the valve, reducing the heavy repetitive routine design work of professional and technical personnel, so that technicians have more energy to improve product technical performance and new product research and development, shorten the cycle, improve labor productivity. Especially in the metal seal butterfly valve field, due to the application of CAD/CAM, there appeared the three-dimensional sealing pair made by Cam NC machining, which made the sealing surface of the valve without any squeeze, abrasion or abrasion, so as to increase the sealing and service life of the butterfly valve in the order of quantity.
Butterfly valve in full open, with a small flow resistance, when opened in about 15 ° to 70° between, and can carry out sensitive flow control, so in the area of large-caliber regulation, butterfly valve application is very common, and will gradually become the dominant valve type. As the butterfly valve plate movement with the wiping nature, so most of the butterfly valve can be used in the media with suspended solids particles, according to the strength of the seal can also be used for powder and granular media.